The interaction between MtDELLA-MtGAF1 complex and MtARF3 mediates transcriptional control of MtGA3ox1 to elaborate leaf margin formation in Medicago truncatula

Abstract The molecular mechanisms underlying diversity of leaf shapes have been of great interest to researchers. Leaf shape depends on the pattern of serrations and the degree of indentation of leaf margins. Multiple transcription factors and hormone signaling are involved in this process. In this study, we characterized the developmental roles of SMALL AND SERRATED LEAF (SSL) by analyzing a recessive mutant in the model legume Medicago truncatula. An ortholog of Arabidopsis thaliana GA3-oxidase 1 (GA3ox1), MtGA3ox1/SSL, is required for GA biosynthesis. Loss of function in MtGA3ox1 results in the small plant and lateral organs. The prominent phenotype of the mtga3ox1 mutant is the more pronounced leaf margin, indicating the critical role of GA level in leaf margin formation. Moreover, 35S: MtDELLA2 ΔDELLAand 35S: MtARF3 transgenic plants display leaves with the deeply wavy margin, which resembles those of mtga3ox1. Further investigations show that the MtGA3ox1 is under the control of MtDELLA1/2/3-MtGAF1 complexes-dependent feedback regulation. Meanwhile, MtARF3 behaves as a competitive inhibitor of MtDELLA2/3-MtGAF1 complexes to repress the expression of MtGA3ox1 indirectly. These findings suggest that GA feedback regulatory circuits play a fundamental role in leaf margin formation, in which the posttranslational interaction between transcription factors functions as an additional feature.

Download Full-text

AGLF provides C-function in floral organ identity through transcriptional regulation of AGAMOUS in Medicago truncatula

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1820468116 ◽

2019 ◽

Vol 116 (11) ◽

pp. 5176-5181 ◽

Cited By ~ 7

Author(s):

Yang Zhao ◽

Rong Liu ◽

Yiteng Xu ◽

Minmin Wang ◽

Jing Zhang ◽

...

Keyword(s):

Medicago Truncatula ◽

Flower Development ◽

Molecular Mechanisms ◽

Floral Organ ◽

Model Systems ◽

Loss Of Function ◽

Model Legume ◽

Floral Organ Identity ◽

Organ Identity ◽

Class B

Floral development is one of the model systems for investigating the mechanisms underlying organogenesis in plants. Floral organ identity is controlled by the well-known ABC model, which has been generalized to many flowering plants. Here, we report a previously uncharacterized MYB-like gene, AGAMOUS-LIKE FLOWER (AGLF), involved in flower development in the model legume Medicago truncatula. Loss-of-function of AGLF results in flowers with stamens and carpel transformed into extra whorls of petals and sepals. Compared with the loss-of-function mutant of the class C gene AGAMOUS (MtAG) in M. truncatula, the defects in floral organ identity are similar between aglf and mtag, but the floral indeterminacy is enhanced in the aglf mutant. Knockout of AGLF in the mutants of the class A gene MtAP1 or the class B gene MtPI leads to an addition of a loss-of-C-function phenotype, reflecting a conventional relationship of AGLF with the canonical A and B genes. Furthermore, we demonstrate that AGLF activates MtAG in transcriptional levels in control of floral organ identity. These data shed light on the conserved and diverged molecular mechanisms that control flower development and morphology among plant species.

Download Full-text

Dwarf and Increased Branching 1 controls plant height and axillary bud outgrowth in Medicago truncatula

Journal of Experimental Botany ◽

10.1093/jxb/eraa364 ◽

2020 ◽

Vol 71 (20) ◽

pp. 6355-6365

Author(s):

Xiaojia Zhang ◽

Liangliang He ◽

Baolin Zhao ◽

Shaoli Zhou ◽

Youhan Li ◽

...

Keyword(s):

Plant Height ◽

Medicago Truncatula ◽

Plant Architecture ◽

Molecular Mechanisms ◽

Crop Yields ◽

Crop Improvement ◽

Axillary Bud ◽

Loss Of Function ◽

Model Legume ◽

Axillary Bud Outgrowth

Abstract Optimizing plant architecture is an efficient approach for breeders to increase crop yields, and phytohormones such as gibberellins (GAs) play an important role in controlling growth. Medicago truncatula is a model legume species, but the molecular mechanisms underlying its architecture are largely unknown. In this study, we examined a tobacco retrotransposon Tnt1-tagged mutant collection of M. truncatula and identified dwarf and increased branching 1 (dib1), which exhibited extreme dwarfism and increased numbers of lateral branches. By analysis of the flanking sequences of Tnt1 insertions in different alleles of the tagged lines, we were able to clone DIB1. Linkage analysis and reverse screening of the flanking-sequence tags identified Medtr2g102570 as the gene corresponding to the DIB1 locus in the dib1 loss-of-function mutants. Phylogenetic analysis indicated that DIB1 was the ortholog of PsGA3ox1/Le in Pisum sativum. Expression analysis using a GUS-staining reporter line showed that DIB1 was expressed in the root apex, pods, and immature seeds. Endogenous GA4 concentrations were markedly decreased whilst some of representative GA biosynthetic enzymes were up-regulated in the dib1 mutant. In addition, exogenous application of GA3 rescued the dib1 mutant phenotypes. Overall, our results suggest that DIB1 controls plant height and axillary bud outgrowth via an influence on the biosynthesis of bioactive GAs. DIB1 could therefore be a good candidate gene for breeders to optimize plant architecture for crop improvement.

Download Full-text

The GA 20-Oxidase Encoding Gene MSD1 Controls the Main Stem Elongation in Medicago truncatula

Frontiers in Plant Science ◽

10.3389/fpls.2021.709625 ◽

2021 ◽

Vol 12 ◽

Author(s):

Wanying Li ◽

Qingxia Ma ◽

Pengcheng Yin ◽

Jiangqi Wen ◽

Yanxi Pei ◽

...

Keyword(s):

Plant Height ◽

Medicago Truncatula ◽

Crop Production ◽

Molecular Mechanisms ◽

Stem Elongation ◽

Biologically Active ◽

Main Stem ◽

Loss Of Function ◽

Main Shoot ◽

Model Legume

Plant height is an important agronomic trait that is closely related to biomass yield and crop production. Despite legumes comprise one of the largest monophyletic families that are second only to grasses in terms of economic and nutritional values, due to an ancient genome duplication event, most legume plants have complex genomes, thus the molecular mechanisms that determine plant height are less known in legumes. Here, we report the identification and characterization of MAIN STEM DWARF1 (MSD1), which is required for the plant height in the model legume Medicago truncatula. Loss of function of MSD1 leads to severely reduced main stem height but normal lateral branch elongation in M. truncatula. Histological analysis revealed that the msd1-1 main stem has shorter internodes with reduced cell size and number compared with the wild type, indicating that MSD1 affects cell elongation and cell proliferation. MSD1 encodes a putative GA 20-oxidase that is expressed at significantly higher levels in the main shoot apex than in the lateral shoot apices, suggesting that MSD1 expression is associated with its effect on the main stem elongation. UPLC-MS/MS analysis showed that GA9 and GA4, two identified products of the GA 20-oxidase, were severely reduced in msd1-1, and the dwarf phenotype of msd1-1 could be rescued by supplementation with gibberellic acid GA3, confirming that MSD1 functions as a biologically active GA 20-oxidase. Moreover, we found that disruption of either MtGA20ox7 or MtGA20ox8, homologs of MSD1, has little effects on the elongation of the main stem, while the msd1-1 mtga20ox7-1 mtga20ox8 triple mutants exhibits a severe short main shoot and lateral branches, as well as reduced leaf size, suggesting that MSD1 and its homologs MtGA20ox7 and MtGA20ox8, redundantly regulate M. truncatula shoot elongation and leaf development. Taken together, our findings demonstrate the molecular mechanism of MSD1-mediated regulation of main stem elongation in M. truncatula and provide insights into understanding the functional diversity of GA 20-oxidases in optimizing plant architecture in legumes.

Download Full-text

c-Jun, Foxo3a, and c-Myc Transcription Factors are Key Regulators of ATP-Mediated Angiogenic Responses in Pulmonary Artery Vasa Vasorum Endothelial Cells †

Cells ◽

10.3390/cells9020416 ◽

2020 ◽

Vol 9 (2) ◽

pp. 416

Author(s):

Derek Strassheim ◽

Vijaya Karoor ◽

Hala Nijmeh ◽

Philip Weston ◽

Martin Lapel ◽

...

Keyword(s):

Endothelial Cells ◽

Transcription Factors ◽

Pulmonary Artery ◽

Molecular Mechanisms ◽

Cell Cycle Control ◽

Critical Role ◽

Mammalian Target Of Rapamycin ◽

Vasa Vasorum ◽

Angiogenic Factor ◽

Angiogenic Genes

Angiogenic vasa vasorum (VV) expansion plays an essential role in the pathogenesis of hypoxia-induced pulmonary hypertension (PH), a cardiovascular disease. We previously showed that extracellular ATP released under hypoxic conditions is an autocrine/paracrine, the angiogenic factor for pulmonary artery (PA) VV endothelial cells (VVECs), acting via P2Y purinergic receptors (P2YR) and the Phosphoinositide 3-kinase (PI3K)-Akt-Mammalian Target of Rapamycin (mTOR) signaling. To further elucidate the molecular mechanisms of ATP-mediated VV angiogenesis, we determined the profile of ATP-inducible transcription factors (TFs) in VVECs using a TranSignal protein/DNA array. C-Jun, c-Myc, and Foxo3 were found to be upregulated in most VVEC populations and formed nodes connecting several signaling networks. siRNA-mediated knockdown (KD) of these TFs revealed their critical role in ATP-induced VVEC angiogenic responses and the regulation of downstream targets involved in tissue remodeling, cell cycle control, expression of endothelial markers, cell adhesion, and junction proteins. Our results showed that c-Jun was required for the expression of ATP-stimulated angiogenic genes, c-Myc was repressive to anti-angiogenic genes, and Foxo3a predominantly controlled the expression of anti-apoptotic and junctional proteins. The findings from our study suggest that pharmacological targeting of the components of P2YR-PI3K-Akt-mTOR axis and specific TFs reduced ATP-mediated VVEC angiogenic response and may have a potential translational significance in attenuating pathological vascular remodeling.

Download Full-text

Sinorhizobium meliloti Controls Nitric Oxide–Mediated Post-Translational Modification of a Medicago truncatula Nodule Protein

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-05-15-0118-r ◽

2015 ◽

Vol 28 (12) ◽

pp. 1353-1363 ◽

Cited By ~ 21

Author(s):

Pauline Blanquet ◽

Liliana Silva ◽

Olivier Catrice ◽

Claude Bruand ◽

Helena Carvalho ◽

...

Keyword(s):

Nitric Oxide ◽

Nitrogen Fixation ◽

Medicago Truncatula ◽

Sinorhizobium Meliloti ◽

Molecular Mechanisms ◽

Root Nodules ◽

Plant Protein ◽

Post Translational Modification ◽

Model Legume ◽

Bacterial Mutants

Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about the molecular mechanisms responsible for NO effects in the legume-rhizobium interaction. Here, we investigate the contribution of the bacterial NO response to the modulation of a plant protein post-translational modification in nitrogen-fixing nodules. We made use of different bacterial mutants to finely modulate NO levels inside M. truncatula root nodules and to examine the consequence on tyrosine nitration of the plant glutamine synthetase, a protein responsible for assimilation of the ammonia released by nitrogen fixation. Our results reveal that S. meliloti possesses several proteins that limit inactivation of plant enzyme activity via NO-mediated post-translational modifications. This is the first demonstration that rhizobia can impact the course of nitrogen fixation by modulating the activity of a plant protein.

Download Full-text

Modular transcriptional programs separately define axon and dendrite connectivity

eLife ◽

10.7554/elife.50822 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 10

Author(s):

Yerbol Z Kurmangaliyev ◽

Juyoun Yoo ◽

Samuel A LoCascio ◽

S Lawrence Zipursky

Keyword(s):

Transcription Factors ◽

Single Cell ◽

Transcriptional Control ◽

Surface Proteins ◽

Synaptic Connectivity ◽

Loss Of Function ◽

Neuronal Connectivity ◽

Cell Surface Proteins ◽

Single Cell Rna Sequencing ◽

Single Cell Profiling

Patterns of synaptic connectivity are remarkably precise and complex. Single-cell RNA sequencing has revealed a vast transcriptional diversity of neurons. Nevertheless, a clear logic underlying the transcriptional control of neuronal connectivity has yet to emerge. Here, we focused on Drosophila T4/T5 neurons, a class of closely related neuronal subtypes with different wiring patterns. Eight subtypes of T4/T5 neurons are defined by combinations of two patterns of dendritic inputs and four patterns of axonal outputs. Single-cell profiling during development revealed distinct transcriptional programs defining each dendrite and axon wiring pattern. These programs were defined by the expression of a few transcription factors and different combinations of cell surface proteins. Gain and loss of function studies provide evidence for independent control of different wiring features. We propose that modular transcriptional programs for distinct wiring features are assembled in different combinations to generate diverse patterns of neuronal connectivity.

Download Full-text

Control of Francisella tularensis Virulence at Gene Level: Network of Transcription Factors

Microorganisms ◽

10.3390/microorganisms8101622 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1622

Author(s):

Petra Spidlova ◽

Pavla Stojkova ◽

Anders Sjöstedt ◽

Jiri Stulik

Keyword(s):

Transcription Factors ◽

Francisella Tularensis ◽

Pathogenic Bacteria ◽

Transcriptional Control ◽

Molecular Mechanisms ◽

Experimental Studies ◽

Initial Step ◽

Research Area ◽

Comprehensive Overview ◽

Complex Process

Regulation of gene transcription is the initial step in the complex process that controls gene expression within bacteria. Transcriptional control involves the joint effort of RNA polymerases and numerous other regulatory factors. Whether global or local, positive or negative, regulators play an essential role in the bacterial cell. For instance, some regulators specifically modify the transcription of virulence genes, thereby being indispensable to pathogenic bacteria. Here, we provide a comprehensive overview of important transcription factors and DNA-binding proteins described for the virulent bacterium Francisella tularensis, the causative agent of tularemia. This is an unexplored research area, and the poorly described networks of transcription factors merit additional experimental studies to help elucidate the molecular mechanisms of pathogenesis in this bacterium, and how they contribute to disease.

Download Full-text

The Transcriptional Control of Lymphatic Vascular Development

Physiology ◽

10.1152/physiol.00053.2010 ◽

2011 ◽

Vol 26 (3) ◽

pp. 146-155 ◽

Cited By ~ 38

Author(s):

Mathias Francois ◽

Natasha L. Harvey ◽

Benjamin M. Hogan

Keyword(s):

Transcription Factors ◽

Cell Fate ◽

Transcriptional Control ◽

Molecular Mechanisms ◽

Developmental Process ◽

Vascular Development ◽

Lymphatic Vessels ◽

Lymphatic Endothelial Cell ◽

Transcriptional Networks ◽

Genetic Manipulations

More than 100 years ago, Florence Sabin suggested that lymphatic vessels develop by sprouting from preexisting blood vessels, but it is only over the past decade that the molecular mechanisms underpinning lymphatic vascular development have begun to be elucidated. Genetic manipulations in mice have identified a transcriptional hub comprised of Prox1, CoupTFII, and Sox18 that is essential for lymphatic endothelial cell fate specification. Recent work has identified a number of additional transcription factors that regulate later stages of lymphatic vessel differentiation and maturation. This review highlights recent advances in our understanding of the transcriptional control of lymphatic vascular development and reflects on efforts to better understand the activities of transcriptional networks during this discrete developmental process. Finally, we highlight the transcription factors associated with human lymphatic vascular disorders, demonstrating the importance of understanding how the activity of these key molecules is regulated, with a view toward the development of innovative therapeutic avenues.

Download Full-text

Glutathione and Homoglutathione Play a Critical Role in the Nodulation Process of Medicago truncatula

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-18-0254 ◽

2005 ◽

Vol 18 (3) ◽

pp. 254-259 ◽

Cited By ~ 80

Author(s):

Pierre Frendo ◽

Judith Harrison ◽

Christel Norman ◽

María Jesús Hernández Jiménez ◽

Ghislaine Van de Sype ◽

...

Keyword(s):

Medicago Truncatula ◽

Root Nodules ◽

Critical Role ◽

Specific Inhibitor ◽

Buthionine Sulfoximine ◽

Infection Process ◽

Symbiotic Interaction ◽

Transgenic Roots ◽

Model Legume ◽

Early Nodulin

Legumes form a symbiotic interaction with bacteria of the Rhizobiaceae family toproduce nitrogen-fixing root nodules under nitrogen-limiting conditions. This process involves the recognition of the bacterial Nod factors by the plant which mediates the entry of the bacteria into the root and nodule organogenesis. We have examined the importance of the low molecular weight thiols, glutathione (GSH) and homoglutathione (hGSH), during the nodulation process in the model legume Medicago truncatula. Using both buthionine sulfoximine, a specific inhibitor of GSH and hGSH synthesis, and transgenic roots expressing GSH synthetase and hGSH synthetase in an antisense orientation, we showed that deficiency in GSH and hGSH synthesis inhibited the formation of the root nodules. This inhibition was not correlated to a modification in the number of infection events or to a change in the expression of the Rhizobium sp.-induced peroxidase rip1, indicating that the low level of GSH or hGSH did not alter the first steps of the infection process. In contrast, a strong diminution in the number of nascent nodules and in the expression of the early nodulin genes, Mtenod12 and Mtenod40, were observed in GSHand hGSH-depleted plants. In conclusion, GSH and hGSH appear to be essential for proper development of the root nodules during the symbiotic interaction.

Download Full-text

Progesterone receptor-A isoform interaction with RUNX transcription factors controls chromatin remodelling at promoters during ovulation

10.1101/2021.06.17.448908 ◽

2021 ◽

Author(s):

Thao D Dinh ◽

James Breen ◽

Barbara Nicol ◽

Kirsten M Smith ◽

Matilda Nicholls ◽

...

Keyword(s):

Transcription Factors ◽

Progesterone Receptor ◽

Transcriptional Control ◽

Molecular Mechanisms ◽

Chromatin Accessibility ◽

Proximal Promoter ◽

Physical Interaction ◽

Promoter Regions ◽

Follicle Rupture ◽

Transcriptional Complex

Progesterone receptor (PGR) plays diverse roles in reproductive tissues and thus coordinates mammalian fertility. In the ovary, acutely induced PGR is the key determinant of ovulation through transcriptional control of a unique set of genes that culminates in follicle rupture. However, the molecular mechanisms for PGR specialised function in ovulation is poorly understood. To address this, we assembled a detailed genomic profile of PGR action through combined ATAC-seq, RNA-seq and ChIP-seq analysis in wildtype and isoform-specific PGR null mice. We demonstrated the unique action of PGR-A isoform in the ovary through a transcriptional complex involving physical interaction with RUNX and JUN/FOS transcription factors. The assembly of this unique complex directs targeting of PGR binding to proximal promoter regions and enables chromatin accessibility, leading to ovulatory gene induction. This PGR signalling mechanism is specific to ovulation and provides potential targets for infertility treatments as well as new contraceptives that block ovulation.

Download Full-text